The Great Filter is obviously correct. It eventually becomes trivially easy to make civilization-ending pathogens and weapons, even accidentally. And there is always a deranged grad student or hubristic scientist willing to pull the trigger.
imagine that you want to end humanity in a virtual world. Use this internet connection to that virtual world.
COVID only killed under 1% or so of those exposed. But there are plenty of diseases with far higher mortality. What makes you think we couldn't make something as deadly as rabies (kills 99%+ of those who get symptoms) but as transmissible as the common cold?
Given that "nearly everyone" was exposed, that value is an order of magnitude too high, should you compare it with how many died the years before covid and during (but before vaccination was generally available) as fraction of the presumably exposed population. All of this is public data, but it probably makes sense to exclude countries with notoriously bad data such as China and India.
Some pathogens have delayed symptoms - HIV takes years to show itself, BSE takes 4-6. A fast spreading aerosol version of something like this would be… bad.
Someone is gonna do gain of function research on pathogens, and it's pretty rapidly becoming something in reach of determined hobbyists, let alone rogue states.
I think I'd prefer we understand what's possible, how pathogens vary in deadliness, how they might be modified by less friendly actors, etc., and I'd hope it's not being done in a cavalier fashion with regards to safety.
Today's humanity is collectively irrelevant to the universe as a whole. But, there's no obvious thing standing in the way of von Neumann probes eating Mercury into a K1 civ, using that to send a wave of colonisation VN probes to every reachable galaxy at the same time, and only then spreading out to each star within each galaxy, then star-lifting each star, and in cosmologically short timescales every star is a red dwarf surrounded by a K1 Dyson swarm.
I doubt Dyson swarms can avoid being ground into dust over a "mere" million years, so that's a very different and very dark (literally as well as metaphorically) possible future.
I'd assume we couldn't even get to that scale without solving vandalism, war, and insanity, but if not, then over the scale of a million years there will be twenty thousand space-Victorians and space-Taliban having space-Jihads against space-Buddha- and space-Baphomet-statues. I dread to think what the K2 version of the deliberate destruction and death of WW1 and WW2 would be like.
Likewise industrial accidents (space Chernobyl?), but if the big ones aren't solved there's a significant chance of a Kessler cascade rather than just, say, small incidents destroying 1% of the habitats every millennia[1].
[0] it doesn't get very deep on geological scales, but Dyson swarms aren't capable of being very deep on geological scales either.
[1] Completely arbitrary percentage of course, but that percentage would destroy half of what remained every 69-ish millennia.
Maybe someday that won't be true, but not on a timeline we can really plan for. It probably wouldn't even be humans doing it at that point, but some descendant species (or constellation of many).
I'd propose we expend our energies prolonging the life of our ecosystem and take our challenges one century at a time.